Deposition of metallic salts from solutions containing them.



H. REES 6t H. L. SULMANJ DEPOSITION 0F METALLIC SALTS FROM SOLUTIONS CONTAINING THEM. APPLICATION FILED AUG.1B, 1911.

1,074,203. Patented Sept. 30; 1913.

v UNITED STATES ATENT OFFl on.

may REES, OF 'LLANsmLnn LAmoRGAN, WALES, AND HENRY LIVING-STONE" suntan, or LONDON ENGLAND, ASSIGNORS TO THE METALS EXTRACTION con PORATION LIMITED, OF LONDON, ENGLAND.

DEPOSITION OF METALLIC TSALTIS FROM SOLUTIONS CONTAINING THEM.

To all'cqhpmz't may concem f Be it lmown that we; HARRY Rams and HENRY LIVINGSTONE SULMAmfsubjects of the King of England,'residing at Llansamlet, Gla'morgan, Wales, and London, England, respectively, have invented certain new and useful Improvements in the Depositiqn of Metallic Salts from Solutions Containing Them, of which the following is a speci- -ficationv Y Y This inventlon relates to improvements in ,the deposition of metallic salts from solutions containing them and has for its object the recovery of certain metallic salts from 15 solution by heating the latter under conditionshereinafter described, such salts'being thereby obtained in an insoluble form, and in a more basic condition thanthat in which they existed when dissolved. I The invention can be applied to the recovery' of salts of copper, zinc, etc., b t is especially applicableto solutions of bisu fite and sulfateof copper or zinc, such as thoseresulting from the-treatment of roasted sim ple or complex ores of copper or zinc with aqueous sulfurous acid which may, or may not contain free'sulfurous acid in addition thereto. Dealing with zinc for example, if such solutions are heated to a temperature of, say, 80 (3., while in mass or bulk, they undergo "little or nov change, unless the period can be prolonged, when some sulfur dioxid is expelled from solution and a small amount of zinc monosulfite may form as a scum on 'the surface or fall as a slight PI'Q' cipitate, not however in. a basic condition; while the sulfate-of, zinc contained thereirfi I however, such solutions be exposed in'films in a heating apparatus such for preference as that hereinafter to be described, 2". e. if a continuous current of liquor be made to flow filmwise over a series of plates or shelves heated either externally, or internally by the gaseous products of fuel combustion, the

- zinc salts are deposited from the solution more or less completely, frequently in a 7 more basic 'conditionithereafter remaining insoluble in the'liquor. These reactions take place though the temperature of the liquor finally escaping. from .the. apparatus may not exceed 80-90 C. Theseparation of the "'nl fltallic salts described is not effected by\ Specification of Letters Patent. P te t Spt, 30, 19 3, Application filed-August 18, 191}. Serial No. 644,798. I

evaporation, but sulfur dioxidresulting from the decomposition of the bis'ulfite and decrease in the bulk of the liquor due to possibly of some monosulfite, escapes with the cooled inert gases from the apparatus.

According to this invention a process for depositing salts of the kinds described from a solution containing them consists in forming a continuously moving thin film of the solution and subjecting it t-o, the action of heat. According to the preferred method of carrylng the lnvention into effect the thin film of thesolutionis passed over a heated surface or is passed in cascade over a number of heated surfaces and in contact with an ascending heated atmosphere.

Apparatusfor carrying out the process, comprises a chamber accommodating several nets of fuel combustion fro-m the furnace B.

shelves arranged in cascade formation, a. I

The liquor containingthe zinc salts 'to' be recovered (for example the solution of zinc 'bisulfite) is contained in atank C, from nately from opposite sides of the tower to give a zigzag passage to the liquors which finally escapeat the bottom'of the tower through the conduit F- and theconduit F to the collecting tank G.

The tank is preferably provided with a draw-01f pipe G. Hot gases from the coke or'other suitably fired stove B pass upward through the openings between the shelves in an opposite direction"tothe. flow of the liquors and heat the lower shelves to a con side'rable degree u on their under sides.

The tower is made owever, of such height that the inert combustion gases which are *WlthOflt chemical action upon the liquors are (acid liquors or gas.

plied with great economy and efiiciency, as the combustion gases are made to impart almost completel cooled before they'escape at the top of t e apparatus through, the chimney H. The tower may be constructed of refractory brick, slabs or other suitable material capable of. resisting the action of The heat is thus appractically all their heat to the liquor and a the metallic salts. derived therefrom.

they may be covered by hinged doors K on the outside of the tower. The pipe D from the'tank C after passing into the tower dips into a small vesselof the liquor, thereby dilute and the precipitation of the zinc sul- I fate therefrom depends to a certain extent forming a seal sothat the gases do not enter the'pipe D: l

A heat-exchange apparatus may be suity'ably arranged .Wlth re ard to the hot outliowing liquors by whic these are caused to impart their heat to the cold inflowing liquors which,-it is sought to precipitate;

thus permitting of a saving in the coke used.

j 'Su'chan apparatus has previously been used aqueous liquids and acids.

forithe' evaporation and concentration'of the issuing liquors are under 100 C. in

temperature, and any small amount of local evaporation taking place in thelower portions-of the tower are' mainly condensed in the upper portions thereof, and returned with the downflowingliquor.

, Sulfur dioxid is evolved from the liquors as-before stated, and after the saturation 'limit of the colder inlet liquors by sulfur dioxid is reachedthe excess-of this gascontinually evolved in the lower portion of the towers, escapes "with the cooled combustion gases, andmay thereafter be utilizedif desired. 'No claim is made per-.s; to'this 05 with the zinc oxid, into a basic sulfate .method of eliminating the sulfur dioxid from aqueous solutions, as it has been employed, in principle, in the concentration of aqueous sulfurous acid. Under these conditions thebehavio-rof such solutions is quite different. from that of the same solutions'when heated in bulk to the'same temperature as that of the liquors finally issuing from the tower. Thus it has been found that monosiilfite of zinc is, readily. separated from the films of ,liquid thus" ar-C treated, and that in some cases it is tially decomposed into zinc oxid with oss of sulfur dioxid; further, that'zi'nc' sulfate is also to a small extent renderedinsoluble possibly being converted by inter-action allow this to lee-effected.

In the present are made to the solution "partially decomposed and it is possible that some small proportion of zinc is formed in this way on the hot-test portion of the shelf plates; the major portion however, is produced by the action of the sulfat of zinc liquors upon zinc oxid arising fr the decomposition of the zinc sulfite, these joint w reactions occurring on the shelves of the precipitation tower.= These separated solids partially escape in the solution issuing fronr the apparatus, and partially remain as film accretions on the inclined plates or shelves,

from which they may be removed period-" ically by scraping; suitable gas-tight doors being .provided inthe sides of thetowers t The solutions employed in the process are upon the proportion of bisulfite which is precipitated from the solution as monosulfite. The zinc sulfate would notpre'cipitate by itself butrequires the precipitation of to a modification of this invention thisdeficiency can be madetgood by adding to the diluteqsolution a su oxid; or zinc-monosulfite These additions h before itis exposed filmwise'on the shelves of the heated tower or the solution maybe subsequently agitated for a short time'with these rea cuts at a temperature of about 80 to 90 The result isthat the zinc as bisulfite in the solution is precipitated as monosulfite and this together with the added monosulfite or zinc ciency' of either zinc oxid or both secures the. precipitation of some of the zinc sulfate in admixture therewith and in a basic condition.

described, the

In the particular apparatus bottom .slabs or shelves of the tower, z. 0. those nearest to the stove, may be heated to a comparatively high temperature, as for example from 300.to 800 (3., or even more; here "the largest and most basic accretionsform. This, however, does not communicate the same degree of temperature to the liquor fihns passing over them, for, as previously stated, the liquors escaping from the tower are as a' whole heated 'to a temperature of .less than 100 C. By increasing the'height of the tower and the heat im-. parted to the liquors by means of the stove gases, increasingly basic precipitates may be obtained. l f' tons. Temperature .of lowermost shelf on' its under side approximately 800 0. Crosssectional area of gas-way at constricted portions opposite the bottom edge of each shaft 0.44 sq. ft. (the area of the gas-way, however, varies at different points of its length).

It is obvious thatthe invention is not confined merely to the type of apparatus herein described, but any equivalent apparatus may be employed which will reproduce the conditions herein indicated and give the desired effect. I

What we claim as our invention and desire to secure by Letters Patent is 1. A process for depositing monosulfite and sulfate of a metal from a solution containing bisufite and sulfate of the metal, which consists in subjecting a continuously moving thin film of the solution to the action of hot gases from a coke fire.

A process for depositing monosulfite and sulfate of a metal from a solution containing bisulfite and sulfate of the metal, which consists in forming a continuously moving thin film of the solution, passing it over a heated surface'and submitting it to the action of hot gases from a coke fire.

3. A process for depositing monosulfite and sulfate of a metal from a solution con taining bisulfite and sulfate of the metal, which consists in forming a continuously moving thin film of the solution, passing it over a number of heated surfaces in cascade and submitting it to the action of hot gases from a coke fire.

4. A process for depositing monosulfite and sulfate of a metal from a solution containing bisulfite and sulfate of the, metal, which consists in forming a continuously moving thin film of the solution and submitting it to the action of hot gases from a coke fire under a gradually increasing temperature. 1 k

5. A' process for treating complex sulfid ores for the extraction of metal therefrom which-consists in forming a solution of bisulfite and sulfate of the metal making up the deficiency of monosulfite salt required to effect the precipitation of the sulfate salt by adding to the dilutesolution a sufliciencyof an oxid thereafter depositing monosulfite and sulfate of the" metal from the solution in an insoluble and basic form by subjecting a continuously moving thin film of the solution to the action of hot gases from a coke fire.

6. A process for depositing monosulfite and sulfate of 'zinc fromja solution containing bisulfite and sulfate of zinc, which consists in subjecting a continuously moving thin film of the solution to the'action of hot gases from a coke fire. v

' 7. A process for depositing monosulfite and sulfate of zinc from a solution containing bisulfite and sulfate of zinc, which consists in forming a continuouslymoving thin film of the solution, passing it over a number of heated surfaces in cascade and submitting 1 ficiency of zinc monosulfite required to effect the precipitation of zinc sulfate by adding to the dilute solution a sufliciency of zmc oxid thereafter depositing monosulfiteand sulfate 0f the zinc from the solution in an insoluble and basic form by forming a continuously moving thin film of the solution,

passing it over a number of heated surfaces in cascade and submitting it to the action'of hot gases from a coke fire.

- In testimony whereof we have signed our names to this specification in the presence of the subscribing witnesses.

HARRY ases. 4 HENRY LIVINGSTONE SULMAN.

\Vitnesses to the signature of Henry Livingstone Sulman:

FREDERICK READ, WILLIAM GEORGE SELLERS. 

